sam cries no matter who is on top.
my favorite variation of samdean would have to be him being the most pathetic lover to grace the earth, regardless of if he tops or bottoms. dean has never been with someone so okay with being humiliated, until sam.
the first time they fuck, dean lets sam top — keyword, lets - because he fears sam might be mind-numbingly vanilla (foolish, what vanilla guy fucks his brother?) and that dean will scare him away with anything beyond that.
dean thinks there is something psychologically wrong with sam, on a level Beyond the Freudian. because sam defaults to begging for permission to come, hunched over dean in the darkness, salt dripping from his weepy eyes and into dean’s panting mouth. dean still has ahold of his leash, even with sam buried inside of him.
the power dean holds is maddening. he is mildly unamused that this dynamic seems exclusive to the bedroom (or the impala). but he also adores and would not so readily give up seeing the curl in sam’s lips as he snarks at him, the blood on sam’s knuckles when he dares punch back.
still, it’s easy to lull sam into that desirable state after their first time. one where sam is apologetic for the littlest of things, one where he latches onto every vowel falling from dean’s mouth like it is scripture. all dean has to do encircle sam’s wrist and tug, and whisper something sternly enough to be interpreted as disappointment. sam’s knees lose agency and his face falls at the same time his limbs do.
it’s therapeutic, to comfort a guilty sam in bed, to talk him through it. dean is never really punishing sam for anything, but he knows sam feels guilt all the same, and dean derives great contentment from soothing his sobs, forgiving his shortcomings over and over and over until sam thinks it is okay to feel good.